JP2006519707A - System and method for electrical feedthrough embedded in a glass-silicon MEMS process - Google Patents

Abstract

A method for providing an electrically conductive path in a hermetically sealed cavity is described. The sealed cavity is formed utilizing a silicon-glass microelectromechanical structure (MEMS) process, which includes a recess (82) on the glass substrate (80) where the electrical conduction path passes into the cavity. Form a recess and a conductive lead (86) around it. A glass layer (92) is deposited over the substrate, in the recesses and over the conductive leads and then planarized to expose a portion (88) of the conductive leads. Silicon is then bonded (154) to the sealing surface of the planarized glass layer, and the wafer (120) is in a cavity where a portion of each lead is sealed and the other portion of each lead is sealed. Configured to be outside the cavity.

Description

  The present invention relates generally to microelectromechanical structure (MEMS) processes, and more particularly to the electrical connection from the inside to the outside of a sealed cavity formed in the MEMS process.

  Bonding a patterned silicon wafer to a glass (usually Pyrex®) substrate is one method of providing a microelectromechanical structure (MEMS). A portion of the silicon wafer is etched, leaving a mechanical silicon structure secured to the glass substrate. Such a process is initialized with a glass wafer. A cavity is formed in the wafer using a wet or dry etching process. The depth of the etch determines the separation gap between the capacitive elements of the structure. A metal layer is deposited on the glass and patterned to form conductive electrodes and interconnects. A heavily boron doped (p ++) epitaxial layer is grown separately from the lightly doped silicon substrate. The pattern is etched into the silicon wafer until it is deeper than the thickness of the epitaxial layer. The glass and silicon wafers are bonded together using anodic bonding. When an etchant that etches lightly doped silicon rather than p ++ silicon is used, the undoped portion of the silicon substrate is removed by etching, leaving a self-supporting microstructure. Such a process is generally referred to herein as a silicon-glass MEMS process.

  The mechanical structure is exposed to the surrounding environment during operation. Therefore, if the structure requires simple protection from the special operating environment or the surrounding environment, protection needs to be done in the packaging step.

  One packaging step is to form a mechanical structure with a silicon-glass MEMS process in a hermetically sealed cavity. A well known method for forming such cavities is to bond a silicon structure containing a recess to a glass wafer. Recesses that do not extend in all directions through the p ++ silicon layer form cavities after bonding. Unfortunately, using this method, it is difficult to create a silicon structure, such as a vibration sensor, that is completely connected by the cavity, rather than being connected to the cavity wall.

  Another method is to bond a second glass wafer containing a recess to the top of a previously fabricated glass / silicon wafer. At least a portion of the silicon structure is a continuous sealing ring that completely surrounds the second silicon structure (ie, vibration sensor) but is not connected. The second glass wafer is connected to the sealing ring but not bonded to the second silicon structure forming the cavity.

  However, it is not possible to extend the electrical lead from outside the cavity into the hermetic cavity without breaking the seal. Sealing is more difficult to achieve because the shape of the electrical conductors forms an uneven topography of the surface of the glass structure. There is a small gap that the conductor forms on the substrate. Such a gap results in a non-planar sealing surface and an unbounded region that breaks the hermetic seal. Anodic bonding is one method that has been used to attempt to alleviate this problem. However, anodic bonding can only be applied to non-planar regions with variations of about 200 angstroms or less, and the long-term leak rate wound on the anodic bonding seal is unknown. Therefore, for wires that extend through a reliable hermetic seal, the metrology used to form the seal should be substantially flat.

  In one aspect, a method is provided for providing an electrical conduction path within a hermetically sealed cavity, wherein the sealed cavity is formed utilizing a silicon-glass MEMS process. The method includes forming a recess in the surface of the glass substrate where the electrical conduction path is passed through the cavity, and forming a conductive lead around the recess. A glass layer is then deposited over the substrate, inside the recess, and over the conductive leads. The deposited glass layer is planarized to a level that exposes a portion of the conductive lead. A sealed surface is formed on at least a portion of the glass layer, and silicon is bonded to the sealed surface of the planarized glass layer. The silicon is positioned such that a portion of each lead is in the sealed cavity and the other portion of each lead is outside the sealed cavity.

  In another aspect, a structure with a hermetically sealed cavity is provided. The structure has at least one electrically conductive path that passes from the outside of the sealed cavity to the inside of the sealed cavity. The structure has a glass substrate with a recess in which electrical signals are passed into a sealed cavity and conductive leads are formed in and around the recess. The structure further includes a glass layer deposited over the substrate, and the glass layer is also deposited over the recesses and the conductive leads. The glass layer is planarized to the level of a portion of the conductive lead around the recess. Silicon is bonded to the planarized glass surface to form cavities. Silicon is fabricated such that a portion of each conductive lead is in a sealed cavity and the other portion of each conductive lead is outside the sealed cavity.

  In yet another aspect, a microelectromechanical system (MEMS) gyroscope is provided that includes a housing, gyroscope electronics disposed within the housing, a structure defining a hermetically sealed cavity within the housing, and Including a tuning fork gyroscope disposed within a hermetically sealed cavity. The structure includes a plurality of electrical feedthroughs that provide electrical conduction between the gyroscope electronics and the tuning fork gyroscope, and a glass substrate with a recess that passes through the interior and exterior of the hermetically sealed cavity. Have The structure also has a glass layer deposited over the substrate and the electrical feedthrough in the recess. The glass layer is planarized to the level of some of the electrical feedthrough around the recess and silicon is bonded to the planarized glass layer. Silicon is manufactured such that a portion of each electrical feedthrough is in a hermetically sealed cavity and another portion of each electrical feedthrough is outside the hermetically sealed cavity.

  In yet another aspect, a method is provided for providing electrical conduction between a tuning fork gyroscope and a gyroscope electronics. The tuning fork gyroscope is placed in a hermetically sealed cavity and the method forms a recess in the glass substrate wherever the electrical path passes through the cavity, and a conductive lead in and around the recess. Having a deposit. A glass layer is deposited over the substrate, in the recesses, and over the leads. The deposited glass layer is planarized to the level of a portion of the leads around the recess, exposing the first and second contacts of each lead. The tuning fork gyroscope is placed in contact with the first contact of the lead, and the gyroscope electronics is connected to the second contact of each lead.

  In another aspect, a method is provided for providing an electrically conductive path within a hermetically sealed cavity formed utilizing a silicon-glass microelectromechanical structure (MEMS) process. The method includes forming a recess in the glass substrate through the electrical conduction path into the cavity, forming a lead extending outside the recess in the recess, depositing a glass deposit filling the recess on the conductive lead, and exposing the end of the lead. And planarizing the glass deposit to the level of the upper surface of the substrate, forming a hermetic seal, and bonding the silicon wafer to the planarized glass deposit and the upper surface of the substrate.

  In yet another aspect, a structure is provided that includes a hermetically sealed cavity and includes at least one electrically conductive path that passes from the outside to the inside of the hermetically sealed cavity. The structure includes a glass substrate having a recess and an upper surface for passing an electrical signal through a sealed cavity, a conductive lead deposited in the concave, and a glass deposit deposited on the conductive lead. The glass deposit has an upper surface that is planarized to the level of the upper surface of the substrate. The structure also has silicon bonded to the upper surface of the glass deposit and the upper surface of the substrate. Silicon is manufactured such that a portion of each conductive lead is in a sealed cavity and the other portion of each lead is outside the sealed cavity.

  In yet another aspect, a method is provided for providing electrical conduction between components. The method forms a recess in a glass substrate where electrical conduction is made, deposits a conductive lead extending outside the recess in the recess, forms a glass deposit on the conductive lead, fills the recess, and conducts electricity. Exposing a portion of the conductive lead for the purpose.

  FIG. 1 is a schematic diagram of a microelectromechanical system (MEMS) gyroscope 10. The MEMS gyroscope 10 has a housing 12 that includes a tuning fork gyroscope (TFG) 14 therein. The housing 12 may be a plastic package, a miniaturized integrated circuit (SOIC) package, a plastic leadless chip carrier (LCC) package, a quad flat package (QFP), or other well known housing in the art. . The housing 12 provides a structure to place the elements of the TFG 14 in the same location and / or to place other elements in other proximal locations within the housing 12. In some embodiments, the TFG 14 is placed in a substantially sealed cavity 16 formed by bonding silicon to a glass substrate. The substantially sealed cavity 16 provides isolation between the sense elements of the TFG 14 and drives the electronics as described below.

  In some embodiments, the TFG 14 includes a proof mass 18, a motor drive comb 20, a motor pickoff comb 22, and a sense plate 24. The preamplifier 26 is contained within the housing 12 and is electrically connected or connects the combination of the proof mass 18 and the sense plate 24 to each other. The preamplifier 26 and the TFG 14 are formed together in a common structure, and in some embodiments are electrically connected. In other embodiments, the preamplifier 26 is electrically connected to the proof mass 24. The output of preamplifier 26 is transmitted to sense electronics 28, and in another embodiment, preamplifier 26 is incorporated within sense electronics 28. Whatever configuration is utilized, the electrical connection between the TFG 14 and the one or two preamplifiers 26 and the sense electronics 28 is functionally present with respect to the gyroscope 10.

  Further, the output 30 of the motor pick-off comb 22 is transferred to the feedback monitor 32. The feedback monitor 32 provides an output signal 34 to the drive electronics 36 that power the motor drive comb 20. In other embodiments, feedback monitor 32 is incorporated within drive electronics 36. Again, connections to the elements of the TFG 14 are made to the feedback monitor 32 and drive electronics 36 so that the gyroscope 10 functions. The MEMS gyroscope 10 can also include a system power source and other operational electronics not shown in FIG. 1 for ease of illustration.

  The motor drive comb 20 excites the proof mass 18 using electrostatic force by applying a voltage between the interdigitated comb teeth of the proof mass 18 and the drive comb 20. The motor pickoff comb 22 monitors excitation or vibration of the proof mass 18 by monitoring the voltage signal at the electrodes of the proof mass 18. The motor pick-off comb 22 outputs a feedback signal to the feedback monitor 32. Feedback monitor 32 provides an output 34 that is input to drive electronics 36. If the proof mass 18 begins to vibrate too early or too late, the drive electronics 36 adjusts the vibration frequency so that the proof mass 18 vibrates at the resonant frequency. Excitation at such a frequency allows for a higher output signal to be generated. Here, the preamplifier 26, the sense electronics 28, the feedback monitor 32, and the drive electronics are collectively treated as gyroscope electronics.

  As described above and illustrated in the figures, an electrical connection should be made between the gyroscope electronics and the sealed cavity of the TFG 14. It is difficult to demonstrate making such a connection while maintaining a seal with respect to the cavity 16, as described and illustrated with respect to FIGS.

  FIG. 2 is a cross-sectional view illustrating one known method of bonding silicon to a glass substrate to form a hermetically sealed cavity 50. The glass substrate 52 includes a bonding surface 54 to which a seal ring 56 also having a bonding surface 58 is anodic bonded. The seal ring 56 shown in such an embodiment is a continuous seal ring that completely surrounds but is not connected to the second silicon structure 60. In some embodiments, the seal ring 56 is made of silicon. For example, the silicon structure 60 is not limited to the tuning fork gyroscope 14 (as shown in FIG. 1), but may be a vibration sensor including such a tuning fork gyroscope 14. The second glass substrate 62 with the bonding surface 64 is substantially bonded to the bonding surface 66 of the seal ring 56, which forms the cavity 50 there, not the second silicon structure 60. In other embodiments, the seal ring 56 is first bonded to the second glass substrate 62. Although referred to as a ring, the seal ring 56 should be understood to include any shape that is useful for forming the cavities required for a particular application.

  FIG. 3 illustrates the structure described through FIG. 2 with the addition of a conductor 70 at a position outside the cavity 50. The components of FIG. 3 that are common to those of FIG. 2 are indicated using the same reference numerals. A conductor 70 is disposed on the glass substrate 52 to provide electrical conduction between the circuitry outside the cavity 50 (not shown) and the silicon structure 60. A single lead 70 is shown, but between the silicon structure 60 and the outer circuit of the cavity 50, for example, between the tuning fork gyroscope 14 (shown in FIG. 1) and the gyroscope electronics. It will be appreciated that there may be instances where multiple conductors 70 are required. FIG. 3 further illustrates that when the lead 70 is utilized, at least a portion of the bonding surface 54 of the glass substrate 52 and at least a portion of the bonding surface 58 of the seal ring 56 are no longer in contact. In addition, because the bonding surfaces 54 and 58 are substantially flat, the area of the bonding surface 58 cannot contact the bonding surface 54 and it is difficult to maintain the hermetically sealed cavity 50. In other words, the routing conductor 70 between the bonding surfaces 54 and 58 jeopardizes the hermetic seal because portions of the bonding surfaces 54 and 58 are separated from each other by the presence of the conductor 70.

  FIG. 4 shows an improved structure for passing electrical signals within a hermetically sealed cavity formed at least in part of a silicon-glass MEMS process. The embodiment illustrated in FIG. 4 utilizes a modified glass substrate 80 in which at least one recess 82 is formed in the glass substrate 80 where it is desired to pass electrical signals through the hermetically sealed cavity 84. A conducting wire 86 is formed in the recess 82 and extends to the upper surface 88 of the substrate 80. In some embodiments, the conductor 86 is made of metal and is conductive.

  The conductor 86 is configured such that the extension 88 extends into the outer region where the seal ring 90 is to be disposed and into the cavity 84 for connection to an electrical circuit. In some embodiments, the seal ring 90 is made of silicon. A glass deposit 92 is placed in the recess 82 and placed on top of the conductor 86 in a manner further described with respect to FIG. Glass deposit 92 provides a bonding surface 94 for seal ring 90. Therefore, the above-described embodiment solves the above-described sealing problem by substantially creating an electrical path below the surface of the glass substrate 80. Further, the substantially flat surface 94 provides a bond with the surface 96 of the seal ring 90 and creates a hermetic seal for the cavity 84 that is necessary for the operation of the silicon structure 98.

  It should be noted that the structure described in FIG. 4 can be manufactured in several ways. For example, the silicon structure 98 is manufactured from a silicon wafer (not shown) disposed on the glass substrate 80, and the seal ring 90 is manufactured from a silicon wafer (not illustrated) disposed on the second glass substrate 62. Can be done. By placing the seal ring 90 and the second glass substrate 62 on the glass substrate 80 (and the glass deposit 92 at the associated location), a sealed cavity 84 is formed. In another embodiment, the seal ring 90 is formed on the glass substrate 80 and the silicon substrate 98 is formed on the second glass substrate 62. Further, the seal ring 90 and the silicon substrate 98 may be formed from a single silicon wafer (not shown) disposed on either the glass substrate 80 or the second glass substrate 62. Whichever method is used, at least a portion of the seal ring is manufactured to form a seal with the glass deposit 92, and a portion of the seal ring 90 is manufactured to form a seal with a portion of the glass substrate 80. As a result.

  FIG. 5 illustrates a process for providing an electrical signal in the cavity while maintaining a hermetic seal around the cavity, similar to the structure illustrated in FIG. Referring to FIG. 5A, the glass substrate 100 has at least one recess 102 formed in the surface 104 of the substrate 100. In certain embodiments, the recesses 102 are etched into the glass substrate 100 even where electrical feedthrough for electrical signals is required. As shown in FIG. 5B, conductive leads 106 are disposed and patterned in and around the recesses 102. FIG. 5C illustrates a glass layer 108 disposed on the entire surface 104 of the substrate 100. The glass layer 108 covers both the recess 102 and the conductive lead 106.

  Referring to FIG. 5D, the glass layer 108 is then planarized using chemical mechanical polishing or other techniques to a level where the first contact 110 and the second contact 112 of the lead 106 are exposed. This process leaves a conductive lead 106 in the recess 102 and provides a substantially planar surface 114 with a surrounding glass surface 116. In other embodiments, the glass layer 108 is planarized to a second level, and then the planarized glass layer is etched to a level at which the first contact 110 and the second contact 112 of the lead 106 are exposed. Is done.

  As shown in FIG. 5E, the first contact 110 and the second contact 112 of the conductive lead 106 are exposed so that, for example, an electrode 118 for an electrical circuit (not shown) can be attached. Referring to FIG. 5F, the silicon wafer 120 is then bonded to the planarized substrate surfaces 114 and 116 (bonding to the surface 116 not shown) so that the conductive leads 106 go under the silicon wafer 120 and The hermetic seal between the silicon wafer 120 and the glass substrate 100 (glass layer 108) is not impaired. Conductive lead 106 is functionally and structurally equivalent to lead 86 (shown in FIG. 4).

  FIG. 6 is a schematic diagram of a MEMS gyroscope 130 that utilizes an electrical feedthrough 132 from a hermetically sealed cavity 134. The hermetically sealed cavity 134 provides an operating environment for a tuning fork gyroscope (TFG) 136. Electrical feedthrough 132 is provided through the use of conductor 86 (shown in FIG. 4). The purpose of TFG 136 here may consider an embodiment of silicon structure 98 (shown in FIG. 4). The substantially sealed cavity 134 provides isolation between the sense element of the TFG 136 and the drive electronics. The preamplifier 26 and the TFG 136, the feedback monitor 32 and the TFG 136, and the drive electronics 36 and the TFG 136 are electrically connected using a conductive wire 86. In other configurations, conductor 86 provides an electrical connection between TFG 136 and the gyroscope electronics, similar to that described with respect to FIG.

  FIG. 7 illustrates another structure 150 for providing a hermetically sealed cavity 152 utilizing a silicon-glass MEMS process. In the structure 150, not the second glass substrate and seal ring (as shown in FIG. 4), a silicon device 154 with a recess 156 formed therein is utilized to form the cavity 152. . To form the cavity 152, the glass substrate 158 is bonded to the silicon device 154.

  In order to provide an electrical path below the surface of the glass substrate 158, the glass substrate 158 includes a recess 160 formed in the glass substrate 158 where it is desired to pass an electrical signal through the hermetically sealed cavity 152. . A conductive lead 162, which in one embodiment is a lead, is formed in the recess 160 and extends to the top surface 164 of the substrate 158. Glass deposit 166 is placed in recess 160 and placed on top of lead 168 using the process described above. The glass deposit 166 can provide a bonding surface 170 for bonding with the bonding surface 172 of the silicon substrate 154, thereby forming a hermetically sealed cavity 152.

  FIG. 8 illustrates another embodiment (a cross-sectional view) of a structure 200 for providing a hermetically sealed cavity 202 utilizing a silicon-glass MEMS process. In the structure 200, the modified glass substrate 204 is utilized in forming the cavity 202 along a seal ring 206 attached to or capable of being attached to the glass substrate 208. At least one recess 210 is formed in the glass substrate 204 where it is desired to pass an electrical signal through the hermetically sealed cavity 202. Conductive leads 212 are formed in the recesses 210 and extend to the upper surface 214 of the substrate 204 for connection to the device 216. In some embodiments, conductive lead 212 is conductive and is manufactured from metal. In some embodiments, the seal ring 206 is made from silicon.

  Lead 212 extends into cavity 202 for connection to device 216, and portion 220 extends to an outer region where seal ring 206 is ultimately disposed for connection to an electrical circuit (not shown). The top surface 222 of the conductive lead 212 is in the recess 210, and the top surface 222 is below the top surface 224 of the substrate 204, making it difficult to create a hermetic seal with the seal ring. To overcome such sealing difficulties, a glass deposit 226 is disposed on the upper surface 222 of the conductive lead 212 within the recess 210. The glass deposit 226 is planarized so that the top surface 228 is formed at the same level as the top surface 224 of the substrate 204. The upper surface 228 of the glass deposit 226 forms a sealed cavity 202 and is ultimately bonded to the seal ring 206 for proper operation of the silicon substrate 230. Thus, the above-described embodiment solves the sealing problem by substantially creating an electrical path under the glass deposit 226. Further, the substantially flat surface (upper surface 228) is bonded to the surface 232 of the seal ring 206 to create a hermetic seal of the cavity 202 that may be required for operation of the silicon structure 230.

  Although not shown, it should be considered that, for example, devices such as MEMS pressure sensors, resonators, temperature sensors, etc. can be constructed utilizing the structures illustrated in FIGS. It should further be noted that the differences between the structures of FIGS. 4, 7 and 8 represent only different manufacturing embodiments for MEMS devices. In addition, other devices including, but not limited to accelerometers, pressure sensor devices, and other MEMS devices may have an electrical feedthrough as described and illustrated with respect to FIGS. Use should also be considered.

  The above-described embodiment for providing an electrical feedthrough within a substantially sealed cavity improves upon known methods of sealing the cavity utilizing an electrical feedthrough. Known methods include attempting a seal over the uneven topography encompassed by both the electrical feedthrough and the glass surface, as described with respect to FIG. The non-planar surface results in non-bonding areas that break the hermetic seal.

  The above-described embodiments provide an electrical feedthrough in a hermetically sealed cavity. However, it should be noted that the methods and structures described herein extend to other applications including conducting electrical conduction into and out of sealed cavities. For example, the described electrical feedthrough can also be utilized to provide electrical conduction between portions of a silicon structure fabricated from a patterned silicon wafer. In a more specific example, electrical conduction may be passed between portions of the silicon structure 98 (shown in FIG. 4) and between portions of the silicon structure 230 (shown in FIG. 8). Such methods extend to providing electrical conduction between any electrical components that can be placed on or attached to a glass substrate.

  The method described herein involves the use of a feedthrough that is substantially embedded under a smooth glass surface and includes providing a better seal between silicon and glass. Thus, while the invention has been described in terms of various embodiments, those skilled in the art will recognize that the invention can be modified within the spirit and scope of the claims.

1 shows a schematic diagram of a MEMS gyroscope. FIG. 4 illustrates a structure formed utilizing a method for creating a hermetically sealed cavity using a silicon-glass MEMS process. FIG. 4 illustrates a structure for passing conductors through a hermetically sealed cavity formed using a silicon-glass MEMS process. Figure 3 illustrates an improved method for passing a lead through a hermetically sealed cavity formed using a silicon-glass MEMS process. The method of FIG. 4 is illustrated sequentially. FIG. 5 is a functional schematic diagram of a MEMS gyroscope showing an area where the electrical feedthrough of FIG. 4 is utilized. FIG. 6 illustrates another embodiment of a structure for providing a lead within an hermetically sealed cavity. FIG. 6 illustrates another embodiment of a structure for providing a lead within an hermetically sealed cavity.

Claims (19)

A method for providing a conduction path in a hermetically sealed cavity (84), wherein the sealed cavity is formed utilizing a silicon-glass microelectromechanical structure (MEMS) process;
Forming a recess (82) in the glass substrate (80) where the conduction path passes through the cavity;
Forming a conductive lead (86) around the recess and
Depositing a glass layer (92) over the substrate, in the recesses and over the conductive leads;
Planarizing the deposited glass layer to the level of the conductive lead so that a portion of the conductive lead is exposed;
Forming a sealing surface (94) on at least a portion of the glass layer;
Bonding silicon to the sealing surface of the planarized glass layer;
Steps
The silicon was positioned so that one part (88) of each lead was in the sealed cavity and the other part of each lead was outside the sealed cavity;
A method for providing a conduction path in a hermetically sealed cavity (84). Bonding silicon to the planarized glass layer (92) comprises:
Bonding a seal ring (90) to the flattened glass layer;
Bonding a seal ring to the second glass substrate (208);
The method of claim 1, comprising steps. Further planarizing the deposited glass layer (108) to the level of the conductive lead (86);
Planarizing the deposited glass layer to expose the first contact (110) and the second contact (112) for each lead;
Attaching electrodes (118) to the first and second contacts of each lead;
The method of claim 1, comprising steps.   Bonding silicon to the planarized glass layer includes bonding silicon (154) to the planarized glass layer (166) such that silicon forms cavities (156). The method of claim 1, wherein: A structure having a hermetically sealed cavity (84), wherein the structure comprises at least one electrically conductive path that passes from outside to inside of the sealed cavity, the structure comprising:
A glass substrate (80) with a recess (82) at a location where an electrical signal is passed through the sealed cavity;
The recess and a conductive lead (86) deposited therearound;
A glass layer (92) deposited over the structure, wherein the glass layer is further deposited over the recess and the conductive lead, the glass layer being the conductive lead around the recess. To a level of part of (88),
Silicon (154) bonded to the planarized glass layer to form a cavity, wherein the silicon is in a cavity in which a portion of each of the conductive leads is sealed, A structure characterized in that it is manufactured such that the other part of the conductive lead is outside the sealed cavity.   The silicon has a seal ring (90) bonded to the flattened glass layer, and the seal ring is configured to be bonded to a second glass substrate (208). The structure according to claim 5. A microelectromechanical system (MEMS) gyroscope (130)
A housing;
Gyroscope electronics (28, 36) disposed within the housing;
A structure defining a hermetically sealed cavity (134) in the housing;
A tuning fork gyroscope (136) disposed within the hermetically sealed cavity, the structure comprising:
A plurality of electrical feedthroughs (132) that provide electrical conduction between the gyroscope electronics and the tuning fork gyroscope;
A glass substrate (80) with a recess (82), wherein the recess passes the electrical feedthrough into and out of a hermetically sealed cavity;
A glass layer (92) deposited over the structure, wherein the glass layer is further deposited over the electrical feedthrough of the recess, and the glass layer is electrically connected around the recess. Flattened to the level of part of the feedthrough (88),
Silicon (154) bonded to the planarized glass layer, wherein a portion of each of the electrical feedthroughs is inside a hermetically sealed cavity and the other of each of the electrical feedthroughs The microelectromechanical system (MEMS) gyroscope (130), wherein the silicon is fabricated such that a portion of is located outside the hermetically sealed cavity.   The silicon wafer (120) has a seal ring (90) bonded to the planarized glass layer (92), and the seal ring is bonded to a second glass substrate (208). The MEMS gyroscope (130) of claim 7, wherein the MEMS gyroscope (130) is configured. A method for providing electrical conduction between a tuning fork gyroscope (14) and a gyroscope electronics (28, 36), wherein the tuning fork gyroscope is disposed within a hermetically sealed cavity (84). ,
Forming a recess (82) in the glass substrate (80) where an electrical path passes through the cavity;
Depositing conductive leads (86) around the recesses;
Depositing a glass layer (92) on the substrate, in the recess and on the leads;
Planarizing the deposited glass layer to the level of a portion of the lead (88) around the recess, exposing a first contact (110) and a second contact (112) for each lead;
Placing a tuning fork gyroscope in contact with the first contact on the lead;
Connecting the gyroscope electronics to a second contact associated with each lead. Bonding silicon (154) to the planarized glass layer (92) to form and seal a hermetically sealed cavity (84);
The silicon was configured such that the first portion (88) of each lead (86) was inside the sealed cavity and the second portion of each lead was outside the sealed cavity;
The method of claim 9. Bonding silicon (154) to the planarized glass layer (92),
Bonding a seal ring (90) to the flattened glass layer;
Bonding the seal ring to a second glass substrate (208);
The method of claim 10, comprising steps.   The method of claim 9, wherein forming the recess (82) comprises etching the recess in the substrate (80).   The method of claim 9, further comprising attaching an electrode (118) to the first contact (110) and the second contact (112) of each lead (86). A method for providing an electrically conductive path in a hermetically sealed cavity (84), wherein the sealed cavity is formed utilizing a silicon-glass microelectromechanical structure (MEMS) process;
Forming a recess (82) in the glass substrate (80) at a location where an electrical conduction path is passed through the cavity;
Forming a lead (88) extending out of the recess (86) in the recess (86);
Depositing a glass deposit (92) over the conductive leads, filling the recesses by the deposition and leaving exposed lead ends;
Planarizing the glass deposit to the level of the upper surface (104) of the substrate so that an airtight seal is formed;
Bonding a silicon wafer (120) to the top surface of the substrate and the planarized glass deposit, one part of each lead is in a sealed cavity and the other part of each lead is in a sealed cavity. The wafer was positioned to be on the outside,
A method characterized by that. Bonding (154) a silicon wafer (120) to the planarized glass deposit (92);
Bonding a seal ring (90) to the flattened glass layer;
Bonding the seal ring to a second glass substrate (208);
15. The method of claim 14, comprising steps. A structure comprising a hermetically sealed cavity (84), the structure having at least one electrically conductive path from outside the cavity to the sealed cavity;
A glass substrate (80) with a recess (82) where electrical signals pass through the sealed cavity and upper surface (104);
Conductive leads (86) deposited in the recesses;
A glass deposit (92) deposited on the conductive leads, the glass deposit comprising an upper surface planarized to the level of the upper surface of the substrate;
(154) silicon bonded to the upper surface of the glass deposit and the upper surface of the substrate, the silicon being partly within the sealed cavity with each conductive lead. The structure is manufactured such that another part of each conductive lead is outside the sealed cavity. A method for providing electrical conduction between components comprising:
Forming a recess (82) in the glass substrate (80) so that electrical conduction is established;
Depositing conductive leads (86) extending out of the recess (88) into the recess;
Forming a glass deposit (92) on the conductive lead, filling the recess,
Exposing a portion of the conductive lead for electrical conduction,
A method comprising steps. Forming a glass deposit (92) on the conductive lead (86);
18. The method of claim 17, comprising depositing glass that fills the recess (82) and covers the glass substrate (80). 19. Exposing a portion (88) of the conductive lead (86) comprises planarizing a glass deposit (92) to expose a portion of the conductive lead. The method described in 1.

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